What are the side effects of the Moderna vaccine?

side effects of the Moderna vaccine
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Here we list some of the most common and uncommon side effects of the Moderna vaccine and discuss the latest trials on pediatric participants

Recently the US pharmaceutical company, Moderna, announced that it will begin testing its COVID-19 vaccine on children aged 6 months to 11 years old. It is the first manufacturer in the US to test its vaccine on infants.

Currently, the vaccine should not be administered to those under the age of 18 due to the unknown side effects.

But what side effects can the rest of the population expect if they are immunised?

Common side effects

The vaccine will be given to you as two 0.5 mL injections and it is recommended that the second dose be administered 28 days after the first.

According to the Medicines and Healthcare products Regulatory Agency around 1 in 10 people can expect to experience very common side effects such as:

  • Tenderness and swelling of the injection site and underarm glands
  • Headache
  • Nausea
  • Vomiting
  • Muscle ache/joint aches/ stiffness
  • Fatigue (tiredness)
  • Chills/ Fever
  • Rash

As with most medicines, mild side effects like those listed above can occur and are not a cause for concern but if you are worried about any side effects you can report it directly to the Coronavirus Yellow Card reporting site. 

Uncommon side effects

Some of the more uncommon/rare or unknown side effects that may still occur include:

  • Temporary one-sided facial drooping (Bell’s palsy)
  • Swelling of the face (It should be noted that swelling of the face can occur in patients who have had facial cosmetic injections.)
  • Severe allergic reactions (anaphylaxis)
  • Hypersensitivity

How effects is the Moderna vaccine?

During clinical trials, the company announced that the vaccine proved to be 94.1% effective and has also shown to work on the South African variant. 

Moderna ingredients

The active substance in each dose is 0.10 mg mRNA encoding the pre-fusion stabilized Spike glycoprotein of SARS-CoV-2 embedded in lipid nanoparticles. It also contains polyethylene glycol/macrogol (PEG) as part of PEG2000-DMG and is a multidose vial which contains 10 doses of 0.5 mL.

Other ingredients listed include:

  • Lipid SM-102, cholesterol
  • 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC)
  • 1,2-Dimyristoyl-rac-glycero-3-methoxypolyethylene glycol-2000 (PEG2000-DMG)
  • Trometamol (tris)
  • Trometamol hydrochloride (tris HCl)
  • Acetic acid
  • Sodium acetate trihydrate
  • Sucrose
  • Water for injections

If you know you are allergic to any of the ingredients listed above then you should not have this particular vaccine.

You should also consult your doctor first if you have a weakened immune system, have a bleeding problem or have a high fever or severe infection.

Moderna expects to deliver its first vaccines to the UK in April.

Contributor Profile


  1. I’ve had a low grade fever starting 24 hours after receiving the first shot, 3 weeks since I tested positive with the virus. It’s day 4 of low grade fever. Normal?

  2. I’m one month out from my first Moderna shot and have been experiencing a range of neurological effects on and off since then – extreme dizziness, tinnitus, nerve shocks, heart palpitations, and muscle spasms. I’ve connected with dozens of other people who are experiencing the same (or worse) and we’ve been largely unable to find medical support. I am not an anti-vaxxer, but we deserve acknowledgment, treatment, and safer vaccines.

    • So have I and it’s frustrating. I can’t complete a full day without falling asleep numerous times in the middle of tasks

    • Omg I’m having the same, I thought I was going crazy. My worst is my eyes I’m getting like dizzy ziggy lines in my eyes and it was freaking me out and being dizzy. I had my jab 15 days ago still feeling weird. And got a rash on my arm

  3. I had a side effect, after the first shot, involving restricted breathing, not really breathing difficulty. Felt like when you have bronchitis and can’t take a full breath. Lasted until the second shot. After second injection this has reappeared. Not all the time but occasionally. Pressure in upper chest concerned my PCP, so he did an EKG, compared it to previous EKG’s and determined it wasn’t heart related.

    • I am going through a similar experience. I never suffered of asthma and I developed it 4 days after my first shot of Moderna. I suffered another very bad asthma attack 4 weeks after my first vaccine. I was lucky that the attack happened just on the eve of the due date for my second vaccine. I don’t even want to think how stronger side effects would have been with a second dose! I would be interested to hear of similar experiences.

  4. I had both Moderna shots and I didn’t get COVID!

    Someone needs to acknowledge that when you get these shots, you won’t get COVID! I think the government is not being very transparent about the fact that two of these shots keep you from getting COVID!

    We need the truth to be exposed! These shots stop COVID!!

  5. It’s been three days since I got the first shot, I awoke this morning to the room spinning out of control, so badly, I won’t drive.
    I too have been feeling like I’m having problems breathing and coughing uncontrollably, It feels like I can’t take a full breath, like when you have Bronchitis, not sure if I should consult my doctor or not?

    • Barbara, Please go to the Dr. The same thing happened to me with the first shot. they gave me antibiotics and steroids. it helped with the inflammation. the second shot not as bad but I have an upper resp infection and have 10 day antibiotics again. They told me people that had gotten covid and then do the shots will have it worse. the symptoms when you had covid you will get back with every shot. They were right.

  6. Only on the arm I had my first vaccination which was several months ago. Started out with chills and then the red blotch would go down my arm, disappear or fade and then appear again. That has stopped, but now, especially at night, my left arm at the place of injection and underneath my arm, down to my hand, I experience strong aches, nerve shocks, and the pain pulses. I can’t figure out why, except for the possibility of a reaction from my first shot. Am I the only one experiencing this?

  7. I am wondering if the Moderna vaccine has an adverse effect of hair loss after both doses are completed. I had actual c Ovid in Dec. 2020 and was told to expect reactions to vaccines bugbear loss wasn’t mentioned. Thanks, Peggy Linder

  8. I took the Pfizer vaccine. I received my second dose on March 25 and I have been experiencing ringing in my head for several weeks with a rise in my blood pressure. Now I have to go to the ENT doctor. The ringing won’t stop.

  9. After the first shot in my right arm the only side effects I had was very sore pain in the injection site for about a week. When I got the 2nd shot I decided to take it in my left arm and now I wish I would have just gotten the one. I suffered severe headaches and shaking uncontrollably at times and very fatigued, I slept approximately 14 hours and was very tired after that for 6 more hours. And of course I had soreness in the injection site for another week. Boy am I’m glad that’s over.

  10. I’ve had some pins and needles feelings in my arms and fingers and sometimes legs. A strange tightness in the chest that is hard to explain. Also, a mild sore throat and headache. These symptoms had me worried, but I read that they’re relatively common with the Pfizer vaccine. Haven’t read as much about Moderna.

  11. I had the moderna vaccine and after my second dose I was out on blood pressure meds for elevated blood pressure. Never had a problem before. Read red pine tea is helpful but haven’t tried it yet!

  12. Hi, I am from the Uk and following approx 2 wks of numb fingers and palpitations I unfortunately suffered a Stroke. I am 45. No problems previously and it would appear there are no issues 1 wk on???
    I have never experienced any issues previously. No weight issues, smoking etc
    I would be very keen to reach out to anyone with similar problems.
    Cheers Paul

  13. Had my first Moderna vaccine in January. Came home from work exhausted. Eleven hours after the shot I rolled over in bed and had pain in my right hip. An hour later tried to get out of bed due to the worst cramp from the hip down to my foot with an additional camp on the outer side of my calf. My husband tried muscle rubs. I took muscle relaxer, ibuprofen, and another pain pill. Nothing worked. The next day was started on prednisone and gabapentin by one of my doctors. Slept in recliner most nights on a heating pad with automatic off timer. As the cramp continued it felt like the nerve going down from my hip to my foot was being strangled. By the third day I lost feeling in my great toe and some of the bottom of my foot and the skin on top of my foot going up from my great toe. Also have a numb spot on the side of my calf where it was cramped. Had second vaccine and had shooting electric shock pain in right great toe. Was really annoying for 36 hours-this is a reported symptom- but I figured The feeling might come back, it didn’t. The doctors say that these are not typical symptoms that are listed as side effects of the vaccine so my regular doctor referred me to PT. Went to physical therapy- made what little decrease in pain I had come roaring back. Also by this time I realized and showed my therapist that I can’t lift the toes on my right foot at all, unlike my left. Physical therapist said to get MRI and doctor finally ordered it after doing Neuro check after I told him I can’t lift my toes. He also realized I have weakness in both feet. MRI is not that bad per doctor. On the night of May 6, almost 4 months after my vaccine I had a far worse back, hip, leg and foot muscle spasm event at night and despite meds, massage and heat I couldn’t stand up. I had to crawl to the bathroom as I was unable to put weight on my right side. I was able to do a walk-in visit at my chiropractor- had started seeing him 1 week after the first spasm. By the next day I was in a wheelchair- thank God for my church having one. I saw my MD on the following Monday(in wheelchair) and got stronger meds and was given three weeks off of work. I was in a wheelchair for 8-10 days. I am now getting injections from pain management and regular visits from the chiropractor. I now walk with a cane and thanks to that muscle spasm, I now have lost feeling in the next two toes. It is now June. From my first shot I was enrolled in V-safe and they send regular text messages to me and I filled them out about my back, hip, leg, and foot. They called two weeks ago and spoke with my husband and asked him to have me fill out an Adverse Event form. We finally were able to talk last week and she said she read my report and blieves it is vaccine related due to the most timing and some of the other reports now coming in.They are with the CDC. The lady and I talked and she said to continue to report to them and that my events will be posted. She was so helpful and made me feel like I’m not crazy. So even if your symptoms aren’t listed, tell your doctor and the V-safe people and the CDC. Hopefully soon, my pain will resolve with chiropractic care, pain managent, and meds. I will
    never take a booster of this shot.


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